Static electricity results when two specific types of materials--one having atoms which tend to part with electrons to adjacent atoms and the other having atoms which tend to tear electrons away from adjacent atoms--are rubbed together. Such materials will thereby take on opposite charges as friction causes electrons to be transferred from the first material to the other. Since charges of opposite polarity attract each other, the amount of "cling" between such materials increases as the friction continues.
The friction between clothes as they tumble within a rotating dryer drum, and between the clothes and the drum's inner surface, will cause a static charge to build in this same fashion. As the various items of clothing become oppositely charged, they will tend to cling to each other and become difficult to separate. Another undesirable effect of such static is that it also attracts and causes lint to cling to the clothes.
Thus, it is desirable that these charges be neutralized or discharged before removing the clothes from the dryer. It is even more desirable to eliminate the charges as they occur, so that even small charges will be dissipated.
In the past, devices for neutralizing static charges have included magnets placed within the dryer so that a magnetic field would project into the drum area. The magnetic field causes electrical currents to be induced within the drum, thereby reducing the concentrations of static charges on specific items of clothes.
The applicant has experimented with magnets in attempting to develop a static neutralizing device, and has found it difficult to figure the correct strength of magnet and the appropriate mounting location to achieve the maximum amount of static neutralizing effect. Also, locating a magnet in close proximity to an electric motor can adversely effect the operation of the motor, thus making the proper positioning of any magnets within the dryer more difficult. Applicant has also found that these types of devices do not entirely remove or neutralize the static charges from the clothes.
Other devices in the prior art use this same approach for neutralizing static charges--introducing a flow of electrons through the tumbling clothes--but do not use magnets. A device described in U.S. Pat. No. 3,161,479, uses the tumbler axle to rotate a belt which develops a static charge. This charge is then conducted through the metal drum to the clothes.
Another method of neutralizing static charges, described in the prior art, involves the discharge of either the positive or negative charges from the dryer drum through an electrical conductor. The clothes are left with a single polarity charge and will thereby repulse, rather than cling, to each other.